Get-Help for Modules you don’t have installed

If you have you ever wished you could get-help on commands for modules you don’t have installed locally, or are having problems using Save-Help to get module help onto servers that don’t have an internet connection because your clients don’t have those modules — I have a solution.

With the new Update-Help command, the PowerShell team has made it possible to Save-Help to disk, and then move that help and update servers that are offline or behind strict firewalls. However, there’s no built-in way to download help for a module that’s not installed on your local client … and you can’t use the output of Save-Help to read the help on your development box if you don’t have the module installed there.

My new module HelpModules aims to solve both those problems with two commands:

New-HelpModule

New-HelpModule will let you generate a simple module stub that contains just enough information to convince Update-Help and Save-Help to do their jobs. What’s more, it works on the pipeline so you can use Invoke-Command to get the module information from remote servers and pipe it straight into New-HelpModule:

Invoke-Command -ComputerName Server1 {
   Get-Module -ListAvailable | Where HelpInfoUri } | New-HelpModule
 

This example would actually list all the modules from a server named “Server1” that have updatable help, generate stubs for them in your local $PSModuleHelpRoot (more about that later), and update the help files (locally).

You can also generate a stub by hand, given the information about the module. In other words, call your mate up on the phone, have them run Get-Module Hyper-V -List | Format-List * and then read you the GUID, Version, and HelpInfoUri … then, you just run:

New-HelpModule Hyper-V '1.0' 'af4bddd0-8583-4ff2-84b2-a33f5c8de8a7' 'http://go.microsoft.com/fwlink/?LinkId=206726'
 

StubFunctions

The second problem we have is that we can’t run Get-Help on commands that don’t exist on our system. There are two ways around that, using this module. The simplest is to just pass the -StubFunctions switch when you’re calling New-HelpModule. This will generate empty function stubs for each command that’s in the original module — they have no parameters, no code, nothing.

StubFunctions are be enough to let Get-Help work on those commands, but you’ll have to add the $PSModuleHelpRoot to your $Env:PSModulePath in order to take advantage of it. The problem with that is that you’ll pollute your session with modules and commands that don’t really exist (or at least, don’t do anything). Incidentally, I promised more information about PSModuleHelpRoot:

PSModuleHelpRoot

This variable is exported by the HelpModules module, and it’s the path to where New-HelpModule will generate modules (and where Get-ModuleHelp will read from: more on that next). The path defaults to a “WindowsPowerShellHelpModules” folder in your Documents directory, but you can set it to anything you like after importing the module.

Get-ModuleHelp

Get-ModuleHelp is basically a simplified version of Get-Help that works straight on the XML files in your $PSModuleHelpRoot modules. Instead of searching for commands, it searches for help.

It basically works the same as Get-Help, so I’m not going to bother with documentation here — the point is, unlike Get-Help, this doesn’t require you to add $PSModuleHelpRoot to your $Env:PSModulePath, and thus doesn’t add empty modules and commands to your session. It’s a little harder to work with, since you have to know what help you have available, and you have to type the full command name (no wildcard support) but that seemed worth it to me.

Get HelpModules from PoshCode.org (you’ll want to save it as “HelpModules.psm1” to a path in your PSModulePath like: ~\Documents\WindowsPowerShell\Modules\HelpModules\HelpModules.psm1

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